(a) Field of the Invention
The present invention relates to a system and method for manufacturing liquid crystal displays.
(b) Description of the Related Art
A liquid crystal display (LCD) is structured having liquid crystal material injected between two substrates. The two substrates have electrodes formed on an inner surface thereof and are joined using a sealant. A plurality of spacers are provided between the substrates to maintain a predetermined cell gap. The liquid crystal material sandwiched between the substrates is dielectrically anisotropic such that, when a voltage of a different potential is applied to electrodes of the substrates to form an electric field, the alignment of liquid crystal molecules of the liquid crystal material is varied. Accordingly, the transmittance of incident light is controlled to enable the display of images.
To manufacture the LCD, orientation layers for orienting the liquid crystal molecules of the liquid crystal material are first provided on the substrates, and an orientation process is performed. Next, spacers are dispersed on one of the substrates, then the sealant is applied to outer edges of the substrates. The sealant is provided with a hole through which the liquid crystal material is to be injected. Following this step, the substrates are aligned then attached through a hot press process. Next, liquid crystal material is injected through the hole of the sealant, after which the hole is sealed.
In the LCD manufacturing process, a plurality of liquid crystal cells, each for producing a single LCD, are formed from a single mother glass. Before the injection of the liquid crystal material, the mother glass is divided into 4, 6 or 8 liquid crystal cells (but not yet cut into these divisions), after which the process is continued on the individual liquid crystal cells.
A serious drawback of the conventional LCD manufacturing process is that it is time-consuming. In particular, the injection of the liquid crystal material must be performed when the space between the substrates is kept vacuum. Both keeping vacuum while maintaining the cell gap, and injecting the liquid crystal material through the small injection hole require substantial amounts of time. Further, since the time required for each individual process may vary according to, for example, the drive method used for a particular LCD, and since there occurs a switch during production from processes performed on the mother glass to those performed on the individual liquid crystal cells, it becomes difficult to provide production equipment for the specific processes in an in-line configuration or to automate manufacture. This substantially limits the productivity improvement. Also, while injecting the liquid crystal material, the spacers become re-positioned by the forces generated from the flow of the liquid crystal material, thereby making it difficult to obtain a uniform cell gap.